Electrical connector and method for manufacturing the same

ABSTRACT

An electrical connector including an insulating housing (20) having surfaces (22,24) for facing mutually facing circuit boards, electrical contacts (50,52) disposed in contact press-fitting holes (26,28) in the insulating housing (20) with central sections of the contacts secured within the insulating housing (20). Contact sections of the electrical contacts (50,52) extend outwardly from the surfaces (22,24) of the insulating housing (20) and are bent to extend along the respective board-facing surfaces (22,24) and spaced therefrom defining spring contact members (54,58) for electrical engagement with conductive pads on the circuit boards.

FIELD OF THE INVENTION

The present invention relates to an electrical connector for dispositionbetween mutually facing circuit boards so that the circuit boards areelectrically connected to each other.

BACKGROUND OF THE INVENTION

Electrical connectors which electrically connect mutually facing circuitboards have been widely used in the past. An electrical connector ofthis type is disclosed in Japanese Patent Publication No. 55-37787 inwhich through-holes are formed inside an insulating housing, andcontacts which are bent in a multiple number of places in order to endowthe contacts with spring properties, are passed through thethrough-holes in the insulating housing and fastened in place. Anotherconnector of this type is disclosed in Japanese Patent Publication No.63-43279 in which contact retaining ribs are formed inside an insulatinghousing, and contacts with spring properties are retained therein bythese ribs.

The contacts used in the conventional electrical connectors describedabove are formed by punching metal plates into predetermined shapesprior to the installation of the contacts in the insulating housing.These contacts have complicated shapes in order to endow the contactswith spring properties; accordingly, the work involved in manufacturingthe contacts and the work required in order to install the manufacturedcontacts within the insulating housing are also complicated. As aresult, the manufacturing process used to manufacture such electricalconnectors is relatively complicated. Furthermore, in the manufacture ofthe contacts, the portions of the punched metal plates that do not formportions of the contacts are discarded. As a result, the utilization ofmaterials is inefficient, and a corresponding increase in the cost takesplace. In addition, the positions of engagement between the contacts andthe circuit boards may be skewed, so that the orientation of theelectrical connector mounted on the circuit boards is not correct, thusleading to the electrical connector providing improper connectionsbetween the contacts and the conductive pads on the circuit boards.

SUMMARY OF THE INVENTION

The present invention was devised to overcome the above drawbacks. Onefeature of the present invention is to provide an electrical connectorwhich utilizes contact materials in an efficient manner, and whichmaintains a stable attitude when mounted on circuit boards. Furthermore,another feature of the present invention is to provide a method formanufacturing an electrical connector in which the manufacturing processis simpler than in conventional methods

The electrical connector of the present invention is to be disposedbetween mutually facing circuit boards so that the circuit boards areelectrically connected to each other, the electrical connector comprisesan insulating housing which has two surfaces that face the respectivecircuit boards, and in which a plurality of contact press-fitting holesthat pass through the two surfaces are formed in a row; and a pluralityof plate contacts, each including a central section that is press-fitinto one of the contact press-fitting holes, and two contact sectionsthat extend from the central section and springably engage therespective circuit boards, the contacts being aligned in a row in theinsulating housing.

Furthermore, the method of the present invention for manufacturing theelectrical connector of the present invention which is to be disposedbetween mutually facing circuit boards so that the circuit boards areelectrically connected to each other, comprises molding an insulatinghousing having surfaces for facing respective circuit boards and a rowof contact press-fitting holes that extend through the surfaces; forminglinear contacts each of which includes a central section and contactsections extending outwardly from the central section; inserting thelinear contacts into the contact press-fitting holes so that the centralsections are press-fitted within a press-fitting section of theinsulating housing and the contact sections extend outwardly from thesurfaces of the insulating housing; and bending the contact sections sothat they extend along the surfaces of the insulating housing as springcontact members for springable engagement with the circuit boards toelectrically connect the circuit boards together.

An embodiment of the invention will now be disclosed by way of examplewith reference to the accompanying drawings in which

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an electrical connector of the presentinvention;

FIG. 2 is a top plan view of FIG. 1;

FIGS. 3 and 4 are side elevational and end views respectively of FIG. 2;

FIGS. 5 and 6 are cross-sectional views taken along lines 5--5 and 6--6respectively of FIG. 3;

FIG. 7 is a top plan view of the insulating housing of the electricalconnector shown in FIG. 1;

FIGS. 8 and 9 are side elevational and end views respectively of FIG. 7;

FIG. 9 is an end view of FIG. 7;

FIG. 10 is an enlarged view of one of a contact press-fitting holes inthe insulating housing;

FIGS. 11 and 12 are cross-sectional views taken along lines 11--11 and12--12 respectively of FIG. 7;

FIG. 13 is a top plan view of an electrical contact for insertion into acontact press-fitting hole of the insulating housing;

FIG. 14 is a side view of FIG. 13;

FIG. 15 is a part cross-sectional view showing a contact section inelectrical engagement with a circuit pad of a circuit board; and

FIG. 16 is a view similar to FIG. 15 showing the contact sectionsoldered to the circuit pad.

DETAILED DESCRIPTION

Electrical connector 10 of the present invention comprises an insulatinghousing 20 which has an upper surface 22 and a lower surface 24 thatface circuit boards (not shown), and a plurality of electrical contacts50 and 52 which are installed in rows in the insulating housing 20.

Contact press-fitting holes 26 and 28 which pass through the uppersurface 22 and lower surface 24 are formed in respective single rows inthe insulating housing 20 along respective sides thereof, so that thecontact press-fitting holes 26 and 28 form a desired pattern as seen inan overall view. Contacts 52 are press-fitted in the contactpress-fitting holes 26, and contacts 50 are press-fitted in the contactpress-fitting holes 28. The central sections of the respective contacts50 and 52 are secured in the contact press-fitting holes 28 and 26.Furthermore, cavities 36 and 38, which communicate with the respectivecontact press-fitting holes 26 and 28, are formed in the insulatinghousing 20. These cavities 36 and 38 are provided in order to insure asufficient bending space for the bending of both end sections of thecontacts 50, 52 projecting linearly from the contact press-fitting holes26 and 28 as described later. When both end sections of the contacts 50,52 are subjected to bending in order to form spring contact members 54and 58, the end sections are bent as far as the interiors of thecavities 36 and 38, so that compensation is made for the return of theend sections due to "spring-back". Engaging members 40 and 42, which actas bending fulcra for the bending of the end sections of the contacts50, 52, are formed in the boundary areas between the contactpress-fitting holes 26 and 28 and the cavities 36 and 38. As shown inFIG. 3, these engaging members 40 and 42 also provide support when thecontact sections 54 and 58 engage the circuit boards and bend.

Furthermore, positioning bosses 30, which are used to position theelectrical connector 10 on one of the circuit boards, are formed at thefour corners of the upper surface 22 of the insulating housing 20.Moreover, flexible fastening legs 32, which are used for the temporaryfastening of the electrical connector 10 to the other circuit board, areformed at the four corners of the lower surface 24. The heights of thebosses 30 and legs 32 are higher than the heights of the contact members54 and 58 extending along the upper and lower surfaces 22 and 24 of theinsulating housing 20. Accordingly, the bosses 30 and legs 32 also actto protect the contact members 54 and 58. Furthermore, it would also bepossible to form positioning bosses similar to the positioning bosses 30instead of the legs 32. Moreover, through-holes 44 used for boltfastening are formed through the upper surface 22 and lower surface 24,and bolts (not shown) are passed through these through-holes 44 therebybolt fastening the electrical connector 10 to the circuit boards.

Next, the contacts and the interior shapes of the contact press-fittingholes will be described.

The contacts 50 and 52 have the same shape; accordingly, only contacts50 will be described. As shown in FIGS. 13 and 14, the shape of thecontacts 50 at the time of press-fitting in the contact press-fittingholes 26 is linear. Contacts with the shape described above can bemanufactured by bending both end sections of these linear contacts.These linear contacts can be manufactured by punching the contacts outof a metal plate. Accordingly, since the waste portions of the metalplate are reduced in size, the utilization of material is veryefficient.

Contact projections 58a and 58b, which engage conductive pads on thecircuit boards, are formed on the respective end sections of thecontacts 50. Furthermore, two projections 60 and 62 are formed on thecentral section of each contact 50. The height of the contactprojections 58a and 58b is approximately 0.08 mm, the height of thesecond projections 60 is approximately 0.52 mm, and the height of thefirst projections 62 is approximately 0.55 mm or higher than secondprojections 60 as may be seen in FIG. 14. As shown in FIG. 10, thecross-sectional shape of the contact press-fitting holes 26 in which thecontacts 50 on which the above projections are formed are press-fittedis a T-shaped cross section which has projecting space 26a formed in thecentral portion. When the contacts 50 are press-fitted in the contactpress-fitting holes 26, the contacts 50 are inserted into the contactpress-fitting holes 26 from the end of the contact projections 58a. Wheneach contact 50 is press-fitted in the corresponding contactpress-fitting hole 26, the contact projection 58a faces in the oppositedirection from the projecting space 26a, so that the contact projection58a passes smoothly through the contact press-fitting hole 26. Thesecond projection 60 enters the contact press-fitting hole 26 first,after which the first projection 62 enters the contact press-fittinghole 26. The second projection 60 proceeds smoothly through the contactpress-fitting hole 26; however, since the height of the projection 62 isgreater than the height of the second projection 60, the projection 62frictionally engages the walls of the insulating housing 20 at a pointslightly to the inside of the entrance of the contact press-fitting hole26. As a result of this frictional engagement, the contact 50 stops. Inthis case, anchoring projections or barbs 64 formed on the contact 50extend outwardly from opposite side edges of the central section to bitewith the walls of contact press-fitting hole 26 in the insulatinghousing 20; as a result, the contact 50 is fastened in place in thecontact press-fitting hole 26. It is shown in FIGS. 13 and 14 that afirst pair of anchoring projections 64 are generally aligned with secondprojection 60, and a second pair of projections 64 are generally alignedwith first projection 62, with the first pair of projections beingspaced axially from the second pair towards the end of the contact thatis inserted into the housing and therefore enter the constriction first,and with projections of the second pair being slightly longer than thoseof the first pair and entering the constriction last.

The contacts 50 fastened in place in the contract press-fitting holes 28as described above, are linear in form. Then, both end sections of eachcontact 50 are subjected to bending with the engaging members 42operating as supporting points, so that contact members 58, which extendalong the upper and lower surfaces 22 and 24 from both ends of thecentral section having the projections 60 and 62, to springably engagethe circuit boards, are formed. The same operation is carried out forcontacts 52 when they are fastened within contact press-fitting holes26. As shown in FIGS. 13 and 14, respective contact projections 58a and58b are formed on these contact members 54 and 58; the contacts 50 and52 are arranged in alternate opposing directions, these contactprojections 58a and 58b are also arranged in like manner. When theelectrical connector 10 is mounted on the circuit boards, the contactprojections 58a and 58b thus arranged electrically engage conductivepads on the circuit boards so that the force acting between the circuitboards and the electrical connector 10 is balanced, thereby causing theelectrical connector 10 to be maintained in a stable attitude andorientation. Furthermore, since contact members are formed on thecontacts 50 by press-fitting the linear contacts 50 in contactpress-fitting holes 28 and subjecting the contacts 50 to bending asdescribed above, manufacture of the electrical connector is simple.

Next, the effect of the contact members will be described with referenceto FIGS. 15 and 16. Here, the contact projections 58a on the contact 50will be described as an example.

In cases where conductive pads 72 are formed on the circuit boards 70 asshown in FIG. 15, the contact projections 58a wipingly engage theseconductive pads 72 with a high contact pressure; accordingly, a highelectrical connection reliability is obtained. On the other hand, incases where conductive pads 72 have flow solder or the like 76 thereonlocated on the circuit boards 70 as shown in FIG. 16, the areassurrounding the contact projections 58a on the contacts 50 engage thesolder 76, so that the contact projections 58a do not sink into thesolder 76 any further than is necessary. Accordingly, as in the case ofFIG. 15, a high electrical connection reliability is obtained.

In the electrical connector of the present invention, as was describedabove, contacts are press-fitted in a plurality of contact press-fittingholes which are arranged in rows of an insulating housing. Accordingly,the force acting between the electrical connector and the circuit boardson which the electrical connector is mounted is balanced, so that theelectrical connector is maintained in a stable attitude and orientation.Furthermore, since each of the contacts comprises a central section andcontact sections which extend from the central section, contacts withthis shape can be manufactured by press-fitting linear contacts in thecontact press-fitting holes, and then bending the end sections of thecontacts. Such linear contacts can be manufactured by punching a metalplate; accordingly, the discarded portions of the metal plate are small,so that the utilization of material is very good and economical.

Furthermore, in the method according to the present invention formanufacturing an electrical connector, an insulating housing is moldedwith press-fitting holes, linear contacts are formed, and these linearcontacts are press-fitted in the contact press-fitting holes in theinsulating housing, after which both end sections of the linear contactsare bent so that spring contact sections extend along opposed surfacesof the insulating housing. Accordingly, there is no need to manufacturecontacts which have a complicated shape, and the electrical connectormanufacturing process is therefore simplified.

The invention is claimed according to the following:
 1. An electricalconnector for disposition between mutually facing circuit boards and forelectrical connection with conductive pads on the circuit boardscomprises an insulating housing (20) having surfaces (22,24) for facingthe respective circuit boards and holes (26,28), electrical contacts(50,52) disposed in the holes (26,28) including contact members (54,58)characterized by:said holes (26,28) are contact press-fitting holes inwhich the electrical contacts (50,52) in linear form are inserted withcentral sections of the contacts secured inside the insulating housingand contact sections extend from the central sections beyond therespective surfaces (22,24) of the insulating housing, said contactsections being bent to extend along the respective surfaces and spacedtherefrom defining spring contact members (54,58) for electricalengagement with the conductive pads on the circuit boards, and each saidcontact press-fitting hole (26,28) includes a constriction inwardly fromentrances along said surfaces (22,24), and each said contact centralsection includes a first projection (62) and a second projection (60)spaced axially therefrom that cause an interference fit within saidconstriction.
 2. An electrical connector as claimed in claim 1 whereinsaid contact press-fitting holes (26,28) extend from respective saidsurfaces in rows adjacent to respective opposing sides of saidinsulating housing.
 3. An electrical connector as claimed in claim 2,wherein the contact press-fitting holes (26) along one said side of theinsulating housing (20) are offset with respect to the contactpress-fitting holes (28) along the other side of the insulating housing(20).
 4. An electrical connector as claimed in claim 3, wherein thespring contact members (58) of electrical contacts (50) extend alongsurfaces (22, 24) in one direction whereas the spring contact members(54) of electrical contacts (52) extend along surfaces (22, 24) in anopposite direction from said one direction.
 5. An electrical connectoras claimed in claim 1, wherein engaging members (40, 42) are provided insaid insulating housing (20) which define fulcra against which thecontact sections engage for bending the contact sections so that theyextend along the surfaces (22, 24) as spring contact members (54, 58).6. An electrical connector as claimed in claim 1, wherein positioningbosses (30) and flexible legs (32) are provided on insulating housing(20) for positioning the connector on the circuit boards.
 7. Anelectrical connector for disposition between mutually facing circuitboards and for electrical connection with conductive pads on the circuitboards, comprising:an insulating housing having surfaces for facing therespective circuit boards and holes, electrical contacts in linear formdisposed in respective said holes and including respective contactmembers at opposed ends thereof; said holes being contact press-fittingholes in which said contacts are inserted with central sections of saidcontacts secured inside said housing and said contact sections extendfrom said central sections beyond respective said surfaces, said contactsections being bent to extend along and spaced from said respectivesurfaces defining spring contact members deflectable toward saidrespective surfaces upon electrical engagement with said conductive padson said circuit boards, and each said contact press-fitting holeincludes a constriction inwardly from entrances along said surfaces, andeach said contact central section includes a first projection and asecond projection spaced axially therefrom that cause an interferencefit within said constriction.
 8. An electrical connector as claimed inclaim 7 wherein said contact press-fitting holes (26,28) extend fromrespective said surfaces in rows adjacent to respective opposing sidesof said insulating housing.
 9. An electrical connector as set forth inclaim 8 wherein said contact press-fitting holes along one side of saidhousing are offset with respect to said contact press-fitting holesalong an opposed side of said housing.
 10. An electrical connector asset forth in claim 9 wherein said spring contact members of alternatingones of said contacts extend along said respective surfaces in opposingdirections.
 11. An electrical connector as set forth in claim 7 whereinengaging members are provided in said housing that define fulcra againstwhich said contact sections engage for bending said contact sections toextend along said respective surfaces to become spring contact members.12. An electrical connector as set forth in claim 7 wherein positioningbosses and flexible legs are provided on said housing for positioningthe connector on said circuit boards.
 13. An electrical connector as setforth in claim 1 wherein said constriction is T-shaped in cross-section.14. An electrical connector as set forth in claim 13 wherein each saidcontact (50,52) includes a board-connecting projection (58a, 58b) at anend of said contact section (58), and said first central sectionprojection (62) is higher than said board-connecting projection (58a,58b) permitting said contact section to pass freely through saidconstriction during connector assembly.
 15. An electrical connector asset forth in claim 14 wherein each said second projection (60) is spacedaxially from said first projection (62) toward an end of said contactthat is inserted into said housing (20) during assembly, and each saidcentral section further includes barbs (64) that extend outwardly fromopposing side edges thereof to penetrate adjacent wall surfaces of saidhousing (20) along said constriction upon insertion of said contact(50,52) in a respective said contact press-fitting hole (26,28).
 16. Anelectrical connector as set forth in claim 15 wherein each said contactcentral section includes a first pair of barbs adjacent said secondprojection (60) and a second pair of barbs adjacent said firstprojection (62), and said barbs of said second pair extend outwardlyfarther than said barbs of said first pair.
 17. An electrical connectoras set forth in claim 7 wherein said constriction is T-shaped incross-section.
 18. An electrical connector as set forth in claim 17wherein each said contact includes a board-connecting projection at anend of said contact section, and said first central section projectionis higher than said board-connecting projection permitting said contactsection to pass freely through said constriction during connectorassembly.
 19. An electrical connector as set forth in claim 18 whereineach said second projection is spaced axially from said first projectiontoward an end of said contact that is inserted into said housing duringassembly, and each said central section further includes barbs thatextend outwardly from side edges thereof to penetrate adjacent wallsurfaces of said housing along said constriction upon insertion of saidcontact in a respective said contact press-fitting hole.
 20. Anelectrical connector as set forth in claim 19 wherein each said contactcentral section includes a first pair of barbs adjacent said secondprojection and a second pair of barbs adjacent said first projection,and said barbs of said second pair extend outwardly farther than saidbarbs of said first pair.